Comtech EF Data RCU101 - Manual (Page 20)

Operation RCU101 1:1 Protection Switch
Page 3-2 TM055 - Rev. 2.2
Primary Backup Action
0 0 No action. Whoever was online, stays online.
1 0 Backup converter is placed online.
0 1 Primary converter is placed online.
1 1 No action. Whoever was online, stays online.
In addition to providing the switching logic, the RCU101 provides each converter with 4 ID bits that tell
the particular converter whether it is the primary or backup converter. The ID bits are as follows:
ID Bits Meaning
1010 Backup
1011 Primary
3.2 Manual/Auto Mode Selection Switch
The Manual/Auto mode selection switch is located on the front of the RCU101 and is used in the
following manner:
When the switch is placed to the far left (PRI), the primary converter is placed online and will stay
online even if it faults.
When the switch is placed to the far right (BU), the backup converter is placed online and will stay
online even if it faults.
When the switch is placed in the middle position, it will automatically switch to the backup when a fault
is detected in the online converter.
If the front panel switch is accidentally left in the manual mode, the RCU101 can be placed in the auto
mode remotely by sending a Manual Command followed by an Auto Command to the converter that
was deselected by the front panel switch. (See the applicable converter manual for more details).
3.3 Switch LEDs
The are two sets of identical switch LEDs, one set for the primary converter and one for the backup
converter. Their meanings are the same.
Online LED - The Online LED indicates that the corresponding converter has been placed online by
the switch.
Standby LED - The Standby LED indicates that the corresponding converter is in Standby.
Fault LED - The Fault LED indicates that the corresponding converter is currently faulted.
Manual LED - The MANUAL LED indicates that the converter has been manually selected and will
stay there.
3.4 Troubleshooting and/or Replacing a Faulted Converter
Prior to testing or replacing a faulted converter it is strongly recommended that the mode selection
switch be set to manually select the converter that is currently online. Once the faults on the faulted
converter have been cleared (or the converter has been replaced), the converter can be placed in the
standby by moving the mode selection switch back to the center, thus placing the switch in auto mode.
Note: If the switch is left in the middle (auto) position while tests are being performed on a converter
that is not faulted, and the online converter faults, the switch will automatically toggle control and data
to the converter under test. This can result in unwanted operation when the converter under test is not
at the same frequency or gain levels as the online converter.